Defining Next Frontier of Mobile Multi-Core Processing

Mobile devices (smartphones and tablets included) have grown popular in the last several years, but they have also fallen victim to specmanship.

As we reported last week, the Taiwanese company is sampling a new quad-core SoC using ARM big.LITTLE architecture for the tablet market. The difference in this new quad-core SoC solution is that MediaTek is adding HMP capability to the SoC.

The Samsung Exynos 5 Octa is another SoC using the big.LITTLE architecture, but MediaTek and Samsung have implemented it differently. The Exynos 5 Octa uses what Samsung calls cluster migration -- the same technique others have used with big.LITTLE implementations. The CPU migration mode moves jobs between clusters of cores. When a high-performance operating point exceeds the capabilities of the quad A7s, the scheduler shuts them down and moves everything to the A15s.

MediaTek is adopting the HMP approach, which it says can assign individual threads to the best core, thus promising better results.

"In Samsung's case, either the big or the LITTLE cores are running, but not simultaneously," Mark Hung, wireless research vice president at Gartner, told us. In MediaTek's case, one, two, three, or all four cores may be running.

Mike Demler, senior analyst at the Linley Group, gave us this explanation for our post last week:

With MediaTek's HMP, the operating system still sees a quad-core CPU, but it can assign (or shift) a task to any CPU independently. The A15s can run at the same time as the A7s. Tasks can still be moved from one to the other for power-performance optimization.

HMP in an octa-core processor?
Just to be clear, MediaTek's newly announced tablet SoC is a quad-core device. However, the company has also joined the eight-core processor bandwagon. A spokesperson recently confirmed speculation about MediaTek's plan to launch an octa-core solution in the fourth quarter.

MediaTek is distinguishing itself from competitors (such as Samsung) by calling its solution "True Octa-Core" processing. What's so true about it? In MediaTek's opinion, it's the addition of HMP to its Octa-core solutions.

The company says on its website, "MediaTek True Octa-Core intelligently allocates processing power to where it is needed, both on a per-application and per-task basis." A white paper to be released soon (and recently obtained by EE Times) explains the process further:

This architecture reveals a significant departure from the load handling systems of other multi-core solutions – even those with eight cores -- which typically tend to restrict tasks that are too demanding, resulting in poor response times or shutdowns.

It remains to be seen whether HMP will be a defining factor in the multi-core mobile apps processor race. But by becoming the first to adopt HMP, MediaTek is banking on that premise.

JK Shin hit the nail on the head with "the general public won't really notice or care." One core vs. two, yes they will notice & care. Two vs. four? Maybe not so much. Four vs. eight? Really, you must be joking.

Give them longer battery life. They will notice and care about that...a lot!

@Jim: As I am sure you know it's really the infrastructure world which is pushing the boundries in multicore with basestations, routers and servers packing mnay more than eight cores at the high end, including some many core chips from folks like Tilera and etc.

But the tools to extract parallelism seem to be particular to specific workloads and architectures. Ideas may get shared but it seems loike each sector has to re-implement them.

With more mulit-core processing, how much power is compromized? 16 hours battery life for mobile device is also very essential. Also, how does OS and software response to this multi-core beyond quad-core?

One thing to remember is that this is the innovation bed for silicon at the moment. Whether 8 cores is overkill or not, the same innovation achieved from these devices will enable future embedded applications, microservers, and the Internet of Things. Personally, I am more interested in what other applications outside of handsets adopt these solutions and why.

I've found it interesting in dealing with two nearly outdated cell phones (samsung S3 and Motorola Photon Q, both about a year old) the significant lags one experiences with what seems to be "normal use." In the progression of a day, I find that either phone can get pretty laggy. In fairness, we use lots of apps. Most of the phone apps like leaving themselves in memory and learning as much as possible about you. To get an idea, go into the developers options and set "show CPU useage." While this is interesting, then set the background processes to "no background processes" or possibly "at most 2 processes." The phone becomes instantly snappy. However, some google operations won't work. My simple minded take on all of these is that more cores can be helpful with todays phone apps doing such a good job of getting in you business!

Thx Junko for starting a discussion on the performance of Multi Core processors. This is an extremely technical / sensitive topic. It requires further in - depth reporting. But I wonder if EE Times / EDN would devote the resources needed to bring out the critical details as most of this Octa / Hexa ... hype is being enabled by ARM.

Qualcomm called eight cores dumb. I find that odd, given how MediaTek is a pretty smart company and the details of the True Octa-Core architecture have yet to be fully revealed. Rushing to judgment before examination of the implementation - where the proof of viability truly lies - is just plain ignorant.